<!DOCTYPE html>
<html class="reftest-wait">
<head>
<meta charset="UTF-8">
</head>
<body>
<!-- Bug 1219068 -->

<math style="position:absolute; top: 0; font-size:1em;  z-index: 0;" display="block">
<mrow>
  <mo>|</mo>
  <mrow>
    <mi>f</mi>
    <mrow>
      <mn>(</mn>
      <mi>x</mi>
      <mn>)</mn>
    </mrow>
    <mn>-</mn>
    <mrow>
      <mi>f</mi>
      <mrow>
        <mn>(</mn>
        <msub>
          <mi>x</mi>
          <mn>0</mn>
        </msub>
        <mn>)</mn>
      </mrow>
    </mrow>
  </mrow>
  <mo>|</mo>
</mrow>
</math>
<div id="hider"
     style="position:absolute; top:0; left:0; background-color:green;
            height:1em; width:100%; z-index:1; padding-top:5px;
            padding-bottom:5px; visibility:hidden" />
  <script>
    function obscureMathML() {
      var hider = document.getElementById("hider");
      hider.style.visibility="visible";
      // The math should now be completely obscured

      document.documentElement.removeAttribute("class");
    }
    window.addEventListener("MozReftestInvalidate", obscureMathML, false);
  </script>
</body>
</html>
